نتایج جستجو برای: alpha hydroxy ketones

تعداد نتایج: 238507  

Journal: :Journal of the American Chemical Society 2002
K C Nicolaou T Montagnon T Ulven P S Baran Y-L Zhong F Sarabia

New synthetic technologies for the preparation and elaboration of alpha-tosyloxy ketones in solution- and on solid-phase are described. Both olefins and ketones serve as precursors to these relatively stable chemical entities: olefins via a novel one-pot epoxidation, arylsulfonic acid displacement, and oxidation sequence, and ketones by direct exposure to arylsulfonic acids in the presence of d...

2016
Esteban Matador David Monge Rosario Fernández José M. Lassaletta

An efficient, scalable and operationally simple one-pot, 2-step strategy for the nucleophilic formylation of trifluoromethyl ketones is presented. The key step is an unprecedented diaza-carbonyl-ene reaction of formaldehyde tert-butyl hydrazone and trifluoromethyl ketones under solvent-free conditions. This reaction proved to be very fast, clean and high-yielding, affording densely functionalis...

Journal: :E3S web of conferences 2023

When the finished feed is stored in air, various components are oxidized, resulting deterioration of feed, with release a rich unpleasant odor, taste and formation compounds decomposition products: aldehydes, hydroxy acids, ketones other substances. A method for packaging combined feeds carbon dioxide environment proposed, which involves long-term storage. interacts water, carbonic acid formed,...

Journal: :Chemical communications 2014
Changcheng Jing Dong Xing Wenhao Hu

A Rh2(OAc)4-catalyzed diazo decomposition reaction of diazo esters with 2-aminophenyl ketones is reported. A series of 3-hydroxy-2,2,3-trisubstituted indolines are produced in good yields with excellent diastereoselectivities via an intramolecular aldol-type trapping of ammonium ylides with ketone units.

Journal: :Organic & biomolecular chemistry 2014
Haitao He Chaorong Qi Yanglu Ou Wenfang Xiong Xiaohan Hu Yanwei Ren Huanfeng Jiang

A novel and efficient cascade annulation of tertiary α-hydroxy ketones and dimethyl but-2-ynedioate is reported. The reaction, which only requires a base as the promoter, provides a straightforward access to polysubstituted pyrano[4,3-a]quinolizine-1,4,6(2H)-triones and 2H-pyran-2,5(6H)-diones under very mild reaction conditions.

Journal: :Dalton transactions 2014
Wilma Neumann Markus Hiller Peter Lönnecke Evamarie Hey-Hawkins

Reduction of hydroxy-functionalised carbaboranyl carboxylic acids by organolithium reagents yields the corresponding tertiary alcohols. This is in contrast to exo-polyhedral C-C bond cleavage of unsubstituted carbaboranyl carboxylic acids upon reaction with lithium organyls. The proposed dimeric contact ion pairs may also explain the formation of tertiary alcohols instead of the expected ketones.

Journal: :Organic & biomolecular chemistry 2016
Mei Bai Yong You Yong-Zheng Chen Guang-Yan Xiang Xiao-Ying Xu Xiao-Mei Zhang Wei-Cheng Yuan

An unprecedented reaction between indolin-2-ones and α-substituted ketones has been developed. Using this protocol, a wide range of biologically important 3-hydroxy-3-phenacyloxindole derivatives could be obtained in good yield (up to 93%) under mild reaction conditions. A possible mechanism of this reaction was tentatively proposed based on some control experiments and MS spectrometry analysis.

Journal: :Chemical communications 2015
Aleksandr Grisin Samuel Oliver Michael D Ganton John Bacsa P Andrew Evans

The bismuth-mediated two-component hemiacetal oxa-conjugate addition of γ-hydroxy-α,β-unsaturated ketones with paraformaldehyde affords anti-4,5-disubstituted-1,3-dioxolanes in an efficient and stereoselective manner. The reaction provides a practical, inexpensive and atom-economical approach to these types of heterocycles, which represent useful intermediates for target-directed synthesis and ...

Journal: :Angewandte Chemie 2009
Zachary A Buchan Scott J Bader John Montgomery

Gettin' a little sugar-no alcohol required: A procedure for the direct glycosylation of ketones without a hydroxy intermediate enables the site-selective glycosylation of hydroxyketones at the ketone or the alcohol functionality without the use of protecting groups on the aglycone (see scheme). Site selectivity is controlled by the catalyst structure in hydrosilylation and dehydrogenative silyl...

Journal: :Photochemistry and photobiology 2006
Edward C Lathioor William J Leigh

Absolute rate constants for hydrogen abstraction from 4-methylphenol (para-cresol) by the lowest triplet states of 24 aromatic ketones have been determined in acetonitrile solution at 23 degrees C, and the results combined with previously reported data for roughly a dozen other compounds under identical conditions. The ketones studied include various ring-substituted benzophenones and acetophen...

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